POLYMER DISPERSIONS AND COATING COMPOSITIONS

摘要

Sterically stabilised dispersions of polymer particles of size 0.1 - 10 microns in an aqueous medium are obtained by free radical-initiated polymerisation in the aqueous medium of ethylenically unsaturated monomer at a temperature at least 10.degree.C higher than the glass transition temperature of the polymer to be formed, in the presence as steric stabiliser of a block or graft copolymer of defined characteristics, the aqueous medium being one which is capable of dissolving the monomer to the extent of at least 3% by weight but which is a nonsolvent for the polymer formed the conditions being such that at no time is there present a separate phase of free monomer and the resulting dispersion containing at least 20% by weight of polymer. The dispersions can be formulated into aqueous coating compositions having improved properties.